Some pharmaceutical products are capable of damaging the human auditory system. Technological progress has provided numerous resources to monitor hearing but there still is some controversy regarding the selection of the most sensitive and specific tests. OBJECTIVE: to analyze audiological procedures used in the auditory monitoring of individuals exposed to ototoxic medication. METHODS: we searched the MEDLINE and LILACS literature databases, using terms pertinent to audiological monitoring, ototoxicity and cancer. The pertaining literature analysis identified two procedures often used worldwide for the early detection of auditory lesions induced by ototoxic pharmaceutical drugs: high-frequency audiometry and evoked otoacoustic emissions. Both allow early identification of hearing disorders before changes are seen in conventional pure-tone audiometry and, consequently, before speech understanding is compromised. CONCLUSION: we suggest a hearing monitoring protocol, considering the patients capability to respond to behavioral tests and monitoring timing (first test/follow up). For cancer patients, hearing monitoring should be performed in the patients treatment venue. (+info)
Diagnostic value of microtympanometry in primary care.
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OBJECTIVE: To determine the reliability, validity, and feasibility of a new hand held microtympanometer. DESIGN: Comparison of microtympanometry by two independent observations of a general practitioner and a nurse, and against a validated reference instrument. SETTING: Primary care health centre of a school for the deaf in the United States. SUBJECTS: 111 schoolchildren receiving a regular check up. MAIN OUTCOME MEASURES: Tympanometry with the Grason Stadler 28, classified with a slightly modified Jerger's classification. RESULTS: Interobserver reliability was 0.95 (Cohen's kappa). Results of microtympanometry were highly comparable with results of the reference instrument (likelihood ratio of positive results, 161.2). CONCLUSIONS: The microtympanometer could be used in general practice: it is hand held, child friendly, easy to handle, and accurate. (+info)
Effect of exposure to a mixture of solvents and noise on hearing and balance in aircraft maintenance workers.
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Aircraft maintenance workers are exposed to a mixture of solvents in the presence of intermittent noise. For this study these workers exposed to solvent mix and noise, were compared with mill workers exposed to noise alone, printed circuit board operatives exposed to solvents alone and those exposed to none who acted as controls. Tympanometry, acoustic reflex thresholds, transient and distortion product otoacoustic emissions, auditory brainstem potentials, nystagmography and posturography were examined. There was a significant effect on pure tone thresholds for both noise and solvents+noise. The distortion product otoacoustic emissions declined with frequency and exhibited lower DP amplitude with noise compared to solvents and noise group. The transient emissions showed a similar effect. Over 32% of subjects with solvent and noise exposure had abnormalities of the auditory brainstem responses in terms of interwave interval prolongation. The mean acoustic reflex thresholds showed a pattern of differences which differentiate noise from solvent and noise groups. The contralateral pathway appears to be differentially affected by solvent exposure. 32% of subjects in the solvents and noise group had an abnormal posturographic finding. In the solvents and noise group 74% had abnormalities of saccades, 56% of pursuit and 45% of optokinetic nystagmus. (+info)
Hearing loss in aging.
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Aging is a natural consequence of a society developing process. The city of Sao Paulo has almost one million people who are above sixty years of age. Age-related hearing loss equals the total hearing loss resulted from cell degeneration caused by noise exposure, ototoxic agents and the loss caused by disorders and medical treatments. AIM: To study age-related hearing degeneration by means of higher thresholds and hearing sensitivity measures. MATERIALS AND METHODS: Cross-sectional contemporary cohort study in which we assessed 211 elderly patients with mean age of 75.24 years, of whom 61 were females and 150 were males. The subjects were submitted to an interview and a conventional audiometric assessment; and later divided into four groups according to age range. RESULTS: Significant threshold drop in the four established age groups, decrease in speech recognition ratio, and a significant difference regarding gender. CONCLUSION: As age advanced there was a gradual increase in hearing loss, men showed a lower threshold in the 4000 Hz frequency when compared to women, and in the speech intelligibility test there was also a gradual decrease with aging. (+info)
Tympanometry assessment of 61 inbred strains of mice.
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Otitis media (OM) accounts for more than 20 million clinic visits in the United States every year. Resistance to antibiotics has hampered current management of the disease. Identification of genetic factors underlying susceptibility to OM is greatly needed in order to develop alternative treatment strategies. Genetically defined inbred mouse strains offer a powerful tool for dissecting genetic and environmental factors that may lead to OM in mice. Here, we report a study of middle ear function of 61 genetically diverse inbred strains of mice using tympanometry. Of the 61 inbred strains tested, the 129P1/ReJ, 129P3/J, 129S1/SvImJ, 129X1/SvJ, A/HeJ, BALB/cJ, BUB/BnJ, C57L/J, EL/SuzSeyFrkJ, FVB/NJ, I/LnJ, LP/J, NZB/BlNJ, PL/J and YBR/Ei strains exhibited tympanograms that were statistically different from other healthy strains according to parameters including middle ear pressure, volume and compliance. These differences are most likely the result of genetic factors that, when understood, will facilitate prevention and treatment of otitis media in humans. In addition, a negative correlation between age and compliance of the tympanic membrane was discovered. This is the first report to successfully use tympanometry to measure mouse middle ear function, which has been a challenge for the hearing research field because of the mouse's tiny ear size. (+info)
Developmental changes in word recognition threshold from two to five years of age in children with different middle ear status.
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The aims were to: (1) provide word recognition thresholds (WRTs) at 31, 43, and 61 months of age; (2) investigate developmental changes over time; (3) investigate the relationship between OME and WRT, and (4) investigate the relationship between WRT and hearing thresholds. Around 1000 children were tested longitudinally as part of the ALSPAC study, using an adaptive measure of word recognition in quiet. Mean WRTs were 28, 23, and 23 dB (A) at 31, 43, and 61 months, respectively. Normal auditory development is associated with a mean improvement in WRT of 5 dB between age 31 and 61 months. There was a mean increase in WRT of +5 dB and +15 dB when OME was present in one and two ears, respectively. Thus, both unilateral and bilateral OME results in a detrimental effect on hearing ability for speech. Additionally, early and 'persistent' OME is associated with greater disability. However by 61 months, previous OME status was not significant. To our knowledge, this is the largest longitudinal study reporting WRT in preschool children with different middle ear status. (+info)
Non-ossicular signal transmission in human middle ears: Experimental assessment of the "acoustic route" with perforated tympanic membranes.
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Direct acoustic stimulation of the cochlea by the sound-pressure difference between the oval and round windows (called the "acoustic route") has been thought to contribute to hearing in some pathological conditions, along with the normally dominant "ossicular route." To determine the efficacy of this acoustic route and its constituent mechanisms in human ears, sound pressures were measured at three locations in cadaveric temporal bones [with intact and perforated tympanic membranes (TMs)]: (1) in the external ear canal lateral to the TM, P(TM); (2) in the tympanic cavity lateral to the oval window, P(OW); and (3) near the round window, P(RW). Sound transmission via the acoustic route is described by two concatenated processes: (1) coupling of sound pressure from ear canal to middle-ear cavity, H(P(CAV) ) identical withP(CAV)P(TM), where P(CAV) represents the middle-ear cavity pressure, and (2) sound-pressure difference between the windows, H(WPD) identical with(P(OW)-P(RW))P(CAV). Results show that: H(P(CAV) ) depends on perforation size but not perforation location; H(WPD) depends on neither perforation size nor location. The results (1) provide a description of the window pressures based on measurements, (2) refute the common otological view that TM perforation location affects the "relative phase of the pressures at the oval and round windows," and (3) show with an intact ossicular chain that acoustic-route transmission is substantially below ossicular-route transmission except for low frequencies with large perforations. Thus, hearing loss from TM perforations results primarily from reduction in sound coupling via the ossicular route. Some features of the frequency dependence of H(P(CAV) ) and H(WPD) can be interpreted in terms of a structure-based lumped-element acoustic model of the perforation and middle-ear cavities. (+info)
Tympanometry in neonates with normal otoacoustic emissions: measurements and interpretation.
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Tympanometry is used in evaluating middle ear functional conditions. Before six months of age its results may be misleading. High frequency studies aim to provide more valid procedures. AIM: To describe and discuss tympanometric measurements and the interpretation in normal hearing neonates at 226, 678 and 1000Hz. METHOD: 110 neonates that were analyzed had normal otoacoustic emissions and no risk for hearing impairment. The age range was 6 to 30 days. Curves were obtained using the GSI-33-II, at the Divisao de Educacao e Reabilitacao dos Disturbios da Comunicacao, Sao Paulo, in 2004. STUDY DESIGN: Clinical prospective. RESULTS: There was a balance between single and double peak curves at 226Hz. Most of the curves were asymmetric at 678Hz, and single-peaked at 1000Hz. quantitative measurements showed a significant gender difference in the Equivalent Ear Canal Volume at 226Hz and on the Peak Compensated Static Acoustic Admittance at 1000Hz. The English protocol showed that almost 100% of ears were normal at 678 and 1000Hz. CONCLUSION: 1000Hz yielded superior results for characterizing normality. The English protocol was efficient to reduce the variability of tympanometric measurements. Data from this study may be used as a guide for diagnosis using tympanometry in neonates. (+info)